Japanese Patent Application Publication No. 2014-184948 (Patent Literature 1) discloses a pneumatic tire provided with a zigzag main groove having a zigzag periodical pattern. Compared with a straight main groove, a zigzag main groove is increased in the length of the edges, and thereby can increase a scratch frictional force.
In the pneumatic tire disclosed in Patent Literature 1, if the zigzag pitches or pitch lengths of the zigzag main groove are decreased in order to further increase the frictional force on snowy/icy roads, then a land region (blocks, rib) adjacent to the main groove becomes more likely to deform, therefore, the steering stability tends to deteriorate.